HJT battery cutting method and HJT battery piece

Abstract

The invention belongs to the technical field of solar cells, and particularly relates to an HJT cell cutting method and an HJT cell piece. The invention provides a cutting method of an HJT battery. The cutting method comprises the following steps: (1) forming pre-open grooves in two ends of a cutting line of the HJT battery by adopting pretreatment; (2) the HJT battery obtained in the step (1) is placed in a laser cutting area, the front face of the HJT battery serves as a cutting face, laser cutting is conducted along the pre-open groove, and the cutting depth is 40-70%; and (3) carrying out cooling treatment on the cut HJT battery, and meanwhile, carrying out mechanical piece breaking. When the method is used for cutting the HJT battery, the influence of laser cutting on the heat effect of the HJT battery can be reduced, and the prepared HJT battery piece has relatively high electrical performance and relatively low piece breaking rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to a HJT cell cutting method and an HJT cell sheet. Background Art

[0002] Crystalline silicon heterojunction solar cells (HJT) are solar cells with heterojunction structures formed by amorphous silicon thin films and single-crystal silicon substrates. Specifically, HJT solar cells use N-type single-crystal silicon (C-Si) as substrates; after the silicon wafer substrate is texturized and cleaned, intrinsic amorphous silicon thin films (ia-Si: H) and boron- and gallium-doped P-type amorphous silicon (Pa-Si: H) are deposited on the front side in sequence to form a pn heterojunction with the silicon wafer substrate; the back side of the silicon wafer substrate is deposited by depositing intrinsic amorphous silicon thin films (ia-Si: H) and phosphorus-doped N-type amorphous silicon (Na-Si: H) to form a back surface field; transparent conductive oxide films (TCO) are deposited on both sides; and finally, metal-based electrodes are formed on the top layer on both sides of the silicon wafer substrate by screen printing. Therefore, HJT solar cells combine the advantages of crystalline silicon cells and thin-film cells, and have the advantages of high conversion efficiency, low process temperature, high stability, low attenuation rate, and double-sided power generation. There is a large space for cost reduction and efficiency improvement, and the application prospects are broad. It is expected to become the development direction of the new generation of battery technology.

[0003] In the related technology, laser cutting technology is used to perform non-destructive cutting of HJT solar cell slices. The entire cutting interface will be damaged, especially the fragments produced by the transparent conductive oxide film are at the edge of the HJT solar cell slice, which may cause leakage. Therefore, the photoelectric conversion efficiency of the cut HJT solar cell slice will still be lost. Further research is needed to design a HJT solar cell slice and its preparation method, which will help reduce slice damage and improve the photoelectric conversion efficiency of the HJT solar cell slice. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, an embodiment of the present invention proposes a method for cutting HJT batteries, which can reduce the influence of laser cutting on the thermal effect of HJT batteries, and the obtained HJT battery has higher electrical performance and lower breakage rate.

[0005] The HJT battery cutting method according to the embodiment of the present invention comprises the following steps:

[0006] (1) Pre-treating is used to form pre-grooves at both ends of the cutting line of the HJT cell;

[0007] (2) placing the HJT battery obtained in step (1) in a laser cutting area, with the front side of the HJT battery as the cutting surface, and the depth of the laser cutting being 40 to 70%;

[0008] (3) The cut HJT battery is cooled and mechanically broken at the same time.

[0009] The advantages and technical effects brought by the HJT battery cutting method of the embodiment of the present invention are as follows: 1. The method of the embodiment of the present invention performs pretreatment before laser cutting to form pre-grooving, which can reduce the processing time of subsequent laser cutting and reduce the impact of thermal effects caused by laser cutting; 2. The method of the embodiment of the present invention controls the cutting depth to 40-70% during the laser cutting process, and combines the mechanical breaking process to further reduce the impact of thermal effects caused by laser cutting, so that the HJT battery cell has higher electrical performance; 3. The method of the embodiment of the present invention performs cooling treatment after laser cutting, and performs mechanical breaking while cooling. During the cooling process, the battery will form cracks along the cutting line under the cooling effect, and mechanical breaking can reduce the breakage rate of the slices.

[0010] In some embodiments, in step (1), the pretreatment includes at least one of laser etching, photolithography or chemical etching.

[0011] In some embodiments, in step (1), the width of the pre-grooving is 0.1 to 0.15 mm.

[0012] In some embodiments, in step (2), the speed of the laser cutting is 270-330 mm / s.

[0013] In some embodiments, in step (2), the output power of the laser cutting is 35-60W.

[0014] In some embodiments, in step (2), the pulse frequency of the laser cutting is 25 to 35 KHz.

[0015] In some embodiments, in step (2), the depth of the laser cutting is 45-55%.

[0016] In some embodiments, in step (3), a cooling liquid is used for cooling, and the cooling liquid includes at least one of deionized water, methanol or ethanol.

[0017] The embodiment of the present invention further provides a HJT battery cell, which is cut using the above-mentioned HJT battery cutting method. DETAILED DESCRIPTION

[0018] The embodiments of the present invention described in detail below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0019] The HJT battery cutting method according to the embodiment of the present invention comprises the following steps:

[0020] (1) Pre-treating is used to form pre-grooves at both ends of the cutting line of the HJT cell;

[0021] (2) placing the HJT battery obtained in step (1) in a laser cutting area, with the front side of the HJT battery as the cutting surface, and the depth of the laser cutting being 40 to 70%;

[0022] (3) The cut HJT battery is cooled and mechanically broken at the same time.

[0023] The HJT battery cutting method of the embodiment of the present invention performs pretreatment before laser cutting to form pre-grooving, which can reduce the processing time of subsequent laser cutting and reduce the impact of thermal effects caused by laser cutting; the method of the embodiment of the present invention controls the cutting depth to 40-70% during the laser cutting process, and combines the mechanical breaking process to further reduce the impact of thermal effects caused by laser cutting, so that the HJT battery cell has higher electrical performance; the method of the embodiment of the present invention performs cooling treatment after laser cutting, and performs mechanical breaking at the same time as the cooling treatment. During the cooling process, the battery cell will form cracks along the cutting line under the cooling effect, and mechanical breaking can reduce the breakage rate of the sliced ​​pieces.

[0024] In some embodiments, preferably, in the step (1), the pretreatment includes at least one of laser etching, photolithography or chemical etching.

[0025] In some embodiments, preferably, in step (1), the width of the pre-grooving is 0.1-0.15 mm, for example, 0.1 mm, 0.11 mm, 0.12 mm, 0.13 mm, 0.14 mm, 0.15 mm, etc.

[0026] In some embodiments, preferably, in step (2), the speed of the laser cutting is 270 to 330 mm / s. For example, 270 mm / s, 275 mm / s, 280 mm / s, 285 mm / s, 290 mm / s, 295 mm / s, 300 mm / s, 305 mm / s, 310 mm / s, 315 mm / s, 320 mm / s, 325 mm / s, 330 mm / s, etc. When the laser cutting speed is low, the laser acts on the material for a longer time, which has a greater impact on the thermal effect of the battery. In the embodiment of the present invention, the speed of laser cutting is optimized, which is conducive to further reducing the impact of laser cutting on the thermal effect of HJT batteries.

[0027] In some embodiments, preferably, in step (2), the output power of the laser cutting is 35 to 60W. For example, 35W, 40W, 45W, 50W, 55W, 60W, etc. The output power of the laser is proportional to the energy. As the output power increases, the more energy acts on the surface of the battery cell, the greater the thermal effect on the battery. In the embodiment of the present invention, the output power of the laser cutting is preferably selected, which can not only reduce the impact of the thermal effect caused by laser cutting, but also make it easier to control the cutting depth.

[0028] In some embodiments, preferably, in step (2), the laser pulse frequency is 25 to 35 KHz, for example, 25 KHz, 27 KHz, 29 KHz, 31 KHz, 33 KHz, 35 KHz, etc. The laser pulse frequency is preferably within this range, which makes it easier to control the cutting depth within the desired range.

[0029] In some embodiments, preferably, in step (3), the depth of the laser cutting is 45-60%. Such as 45%, 47%, 49%, 51%, 53%, 55%, 57%, 59%, 60%, etc. In the embodiment of the present invention, the cutting depth is controlled within this range, which can effectively reduce the impact of the thermal effect caused by laser cutting and ensure a low fragmentation rate. The cutting depth will directly affect the thermal effect and fragmentation rate caused by laser cutting on the battery. If the cutting depth is shallow, the difficulty of mechanical breaking is increased, thereby increasing the fragmentation rate; if the cutting depth is deep, the thermal effect of laser cutting will have a greater impact, thereby reducing the electrical performance of the electrode sheet.

[0030] In some embodiments, preferably, in step (3), a cooling liquid is used for cooling, and the cooling liquid includes at least one of deionized water, methanol or ethanol.

[0031] The embodiment of the present invention further provides a HJT battery cell, which is cut using the above-mentioned HJT battery cutting method.

[0032] The technical solution of the present invention is described in detail below in conjunction with specific embodiments.

[0033] Example 1

[0034] (1) Using laser etching to form pre-grooves with a width of 0.1 mm at both ends of the cutting line of the HJT cell;

[0035] (2) placing the HJT battery obtained in step (1) in a laser cutting area, taking the front side of the HJT battery as the cutting surface, and performing laser cutting along the pre-grooved surface; wherein the laser cutting speed is 280 mm / s, the laser cutting output power is 40 W, the laser pulse frequency is 30 KHz, and the cutting depth is 50%;

[0036] (3) Deionized water is used to cool the HJT battery after laser cutting, and mechanically break it into pieces to obtain HJT battery sheets.

[0037] Example 2

[0038] (1) Using laser etching to form pre-grooves with a width of 0.15 mm at both ends of the cutting line of the HJT cell;

[0039] (2) placing the HJT battery obtained in step (1) in a laser cutting area, taking the front side of the HJT battery as the cutting surface, and performing laser cutting along the pre-grooved surface; wherein the laser cutting speed is 330 mm / s, the laser cutting output power is 50 W, the laser pulse frequency is 35 KHz, and the cutting depth is 60%;

[0040] (3) Deionized water is used to cool the HJT battery after laser cutting, and mechanically break it into pieces to obtain HJT battery sheets.

[0041] Comparative Example 1

[0042] The cutting method of this comparative example is the same as that of Example 1, except that in step (1), the cutting depth is 75%.

[0043] Comparative Example 2

[0044] The cutting method of this comparative example is the same as that of Example 1, except that in step (1), the cutting depth is 30%.

[0045] Comparative Example 3

[0046] The cutting and method of this comparative example are the same as those of Example 1, except that in step (2), the laser cutting is not followed by cooling, but by direct breaking.

[0047] Compared with the cutting methods of Comparative Examples 1 to 3, the battery cells obtained by the cutting methods of Examples 1 to 2 have better performance and lower breakage rate.

[0048] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A method for cutting a HJT battery, characterized in that: The following steps are involved: (1) Pre-treating is used to form pre-grooves at both ends of the cutting line of the HJT cell; (2) placing the HJT battery obtained in step (1) in a laser cutting area, with the front side of the HJT battery as the cutting surface, and the depth of the laser cutting being 40 to 70%; (3) The cut HJT battery is cooled and mechanically broken at the same time.

2. The HJT battery cutting method according to claim 1, characterized in that: In the step (1), the pretreatment includes at least one of laser etching, photolithography or chemical etching.

3. The HJT battery cutting method according to claim 1 or 2, characterized in that: In the step (1), the width of the pre-grooving is 0.1 to 0.15 mm.

4. The HJT battery cutting method according to claim 1, characterized in that: In the step (2), the speed of the laser cutting is 270 to 330 mm / s.

5. The HJT battery cutting method according to claim 1, characterized in that: In the step (2), the output power of the laser cutting is 35 to 60 W.

6. The HJT battery cutting method according to claim 1, characterized in that: In the step (2), the pulse frequency of the laser cutting is 25 to 35 KHz.

7. The HJT battery cutting method according to claim 1, characterized in that: In the step (2), the depth of the laser cutting is 45-55%.

8. The HJT battery cutting method according to claim 1, characterized in that: In the step (3), a cooling liquid is used for cooling, and the cooling liquid includes at least one of deionized water, methanol or ethanol.

9. A HJT cell, characterized in that: The HJT battery is cut using the HJT battery cutting method according to any one of claims 1 to 8.